Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one more rotor blades. The rotor blades capture kinetic energy from wind using known foil principles, and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
The construction of a modern wind turbine rotor blade generally includes upper and lower shell components bonded at a leading and trailing edge of the blade, spar caps, and one or more shear webs. The skin, typically manufactured from layers of fiber composite and a lightweight core material, forms the exterior aerodynamic foil shape of the rotor blade. The spar caps provide increased rotor blade strength by integrating one or more structural elements running along the length of the rotor blade on both interior sides of the rotor blade. Shear webs are structural beam-like components running essentially perpendicular between the top and bottom spar caps and extending across the interior portion of the rotor blade between the outer skins. Spar caps have typically been constructed from glass fiber reinforced composites, though some larger blades are beginning to include spar caps constructed from carbon fiber reinforced composites.
With conventional constructions, the leading edge of the wind turbine blade is an area of concern. The bonding of the shell components at the leading edge is difficult to control. Overbite or underbite between the shell components can occur, often causing extensive rework of the blade. The thickness of the bond can vary from blade to blade, and can often drift outside of a design tolerance. The leading edge bond between the shell components can result in a blade where the most dimensional uncertainty is at a very critical aerodynamic location on the blade. In addition, the leading edge of the turbine blade is highly susceptible to erosion and weathering, and can be damaged during transportation and erection of the wind turbine. These conditions lead to costly on-site repairs.
Accordingly, there is a need for a wind turbine rotor blade design that addresses at lest certain of the present disadvantages associated with blades having shell components bonded together at the leading edge of the blade.